Muller Equipment Company sells computers for $3,000 each on 1st July 2018, and also gives each customer a 1-year warranty that requires the company to perform periodic services and to replace defective parts. During 2018 , the company sold 1000 computers. Based on past experience, the company has estimated the total 1 -year warranty costs as $50 for parts. In 2018, Muller incurred actual warranty costs (inventory) in 2018 were $20,000. Instructions Prepare entries to record the sale of the computers, the related warranty costs, and any accrual on December 31,2018